Index: lib/csp.js
diff --git a/lib/csp.js b/lib/csp.js
index 5309863ab1bb65b9f8a5318d44ef723d0a6d49e9..6f43c352d9681613ef881fe3a187c2a17969a6ec 100644
--- a/lib/csp.js
+++ b/lib/csp.js
@@ -17,11 +17,11 @@
 
 "use strict";
 
-let {defaultMatcher} = require("matcher");
-let {BlockingFilter, RegExpFilter} = require("filterClasses");
-let {getDecodedHostname} = require("url");
+const {defaultMatcher} = require("matcher");
+const {BlockingFilter, RegExpFilter} = require("filterClasses");
+const {getDecodedHostname} = require("url");
 
-chrome.webRequest.onHeadersReceived.addListener(function(details)
+chrome.webRequest.onHeadersReceived.addListener(details =>
 {
   let hostname = getDecodedHostname(new URL(details.url));
   let match = defaultMatcher.matchesAny("", RegExpFilter.typeMap.WEBSOCKET,